A brand new Rigol spectrum analyzer found its way to my shack a couple days ago and I'm looking forward to using it, and other equipment, to make various tests on QRP (mostly) rigs that would pass under the radar of the ARRL lab.
I previously made those measurements using a combination of my own gear and that at my old work QTH, most recently on the Penntek TR-35 here. Or with the IC-705 here and here. And with the FT-891 (not online).
In both cases (IC-705, FT-891), I was pleased to find my MDS results within 1 or 2 dB of those measured by Rob Sherwood.
Until now, I've lacked my own spectrum analyzer and 2-tone test generator. A 2-TTG is on the way and the new Rigol is the DSA-815-TG with tracking generator. The Rigol's display of my FT-891's spectra is identical to the traces obtained with my work QTH's Rohde & Schwarz.
The main difference (at HF/VHF anyway) between the Rigol and the R&S is that the Rigol is slower to make a scan when resolution BW is at the finer settings - settings not necessary for making plots of harmonic content at HF frequencies.